eCall is an electronic safety system that automatically contacts emergency medical services in the event of a serious road accident. These systems typically consist of a dedicated cellular communications module with an antenna, a GNSS receiver to locate the vehicle in the accident, a microphone and loudspeaker for voice communications, a power supply, and a pushbutton so that the vehicle operator can manually activate the system if he or she chooses. Because a system such as this has the potential to save lives, it’s important that high reliability and correct MSD data transmission are achieved. Of all the different components that make up the eCall system, the GNSS receiver and cellular modem is the most susceptible to failure for factors such as environmental conditions and interference. This application note explains how to better ensure proper performance of these systems through the use of a wideband radio communications tester and a vector signal generator to emulate cellular networks in a lab setting.